Accumulated Other Comprehensive Loss Changes in Composition of Accumulated Other Comprehensive Income or Loss (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Increase (Decrease) in Accumulated Other Comprehensive Loss [Roll Forward]
Balance as of beginning of period	$ (185)	$ (239)	$ (316)
Other comprehensive income (Loss)	(325)	63	76
Other comprehensive income (loss)	(1)	(9)	1
Total other comprehensive income (loss)	(326)	54	77
Balance as of end of period	(511)	(185)	(239)
Foreign currency translation adjustments
Increase (Decrease) in Accumulated Other Comprehensive Loss [Roll Forward]
Balance as of beginning of period	(187)	(250)	(326)
Other comprehensive income (Loss)	(325)	63	76
Balance as of end of period	(512)	(187)	(250)
Unrealized gains on available-for-sale securities
Increase (Decrease) in Accumulated Other Comprehensive Loss [Roll Forward]
Balance as of beginning of period	2	11	10
Other comprehensive income (loss)	(1)	(9)	1
Balance as of end of period	$ 1	$ 2	$ 11